Display devices which are intended to provide an immersive experience normally allow a user to turn his head and experience a corresponding change in the scene which is displayed. Head mounted displays sometimes support 360 degree viewing in that a user can turn around while wearing a head mounted display with the scene being displayed changing as the user's head position is changes.
With such devices a user should be presented with a scene that was captured in front of a camera position when looking forward and a scene that was captured behind the camera position when the user turns completely around. While a user may turn his head to the rear, at any given time a user's field of view is normally limited to 120 degrees or less due to the nature of a human's ability to perceive a limited field of view at any given time.
In order to support 360 degrees of view, a 360 degree scene may be captured using multiple cameras with the images being combined to generate the 360 degree scene which is to be made available for viewing.
It should be appreciated that a 360 degree view includes a lot more image data than a simple forward view which is normally captured, encoded for normal television and many other video applications where a user does not have the opportunity to change the viewing angle used to determine the image to be displayed at a particular point in time.
Given transmission the constraints, e.g., network data constraints, associated with content being streamed, it may not be possible to stream the full 360 degree view in full high definition video to all customers seeking to receive and interact with the content. This is particularly the case where the content is stereoscopic content including image content intended to correspond to left and right eye views to allow for a 3D viewing effect.
In the case of stereoscopic camera rigs, wide angle lenses, e.g., fisheye camera lenses, may be used to capture a wide viewing area. While the general lens geometry may be known, manufacturing differences can result in different lenses having different optical characteristics. For example, two fish eye lenses produced in a single batch of lenses may have different optical defects. In the case of stereoscopic image capture, separate left and right eye views are normally captured using separate cameras of a camera pair. Since the lenses will differ on each of the cameras used to capture the left and right eye images, the differences in the camera optics will result in differences in the captured images of a scene area beyond those expected from the camera spacing between the left and right eye images. Such differences can result in distortions in the left and right eye images which will remain in the images at rendering time if the images are processed taking into consideration the intended lens geometry rather than the actual geometry of the individual lenses.
In the case of stereoscopic systems, differences between left and right eye images are normally interpreted by a human viewer as providing depth information. Unfortunately unintended differences between left and right eye images due to camera lens differences with provide a user with improper depth cues and/or result in other image distortions.
In view of the above discussion it should be appreciated that there is a need for methods and apparatus which can reduce or minimize the effect on image quality, e.g., as maybe perceived by a user of a playback system, of distortions introduced into images by camera lenses which can be used in stereoscopic systems and/or other types of systems.